Answer:
2
Explanation:
4s2 has 2 valence electrons
Valence shell is the shell which is the outermost shell, that is filled in the last, before valence shell is penultimate shell. Therefore 2 valence electron are there in the valence shell.
What is element?Element generally consist of atoms or we can say atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
From our question the electronic configuration of element is given as
1s²2s²2p⁶3s²3p⁶4s²
Valence electron is the one which is present in the outermost shell or orbit. So, form above electronic configuration we can say that 4 is the outermost shell and in this shell 2 electron is present. Therefore 2 electron are there in the valence shell as valence electron.
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Write a balanced chemical equation for the complete combustion of methanol, ethanol, propanol, butanol and paraffin wax(C25H52). This information will be needed for the experiment. Transfer the answer to the data sheets also. (10 pts)
Answer:
Explanation:
1. Methanol:
CH3OH + O2 ---> CO2 + 2H2O
2. Ethanol:
C2H5OH + 3O2 ----> 2CO2 + 3H2O
3. Propanol:
2C3H7OH + 9O2 ------> 6CO2 + 8H2O
4. Butanol
C4H9OH + 6O2 -------> 4CO2 + 5H2O
5. Paraffin Wax:
C25H52 + 38O2 ----> 25CO2 + 26H2O
Which best describes the energy change that takes place during deposition?
Heat energy released by the substance
Heat energy is maintained by the substance
Heat energy is slowly gained by the substance
Heat energy is quickly absorbed by the substance
Answer:
heat energy released by the substance
The energy change that takes place during deposition is that heat energy is released by the substance. This statement is true about deposition.
Deposition is a phase transition that occurs when a gas is converted directly to a solid without passing through the liquid state. During deposition, energy is released by the gas particles and absorbed by the surface, resulting in a decrease in the energy of the gas particles and an increase in the energy of the surface particles.As a result, the substance releases heat energy as it changes from a gas state to a solid state.
Therefore, the correct option is:Heat energy released by the substance.
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The table compares vapor pressure values for water ethanol and diethyl ether Add six temperatures determine the approximate normal boiling point for each substance what do the data suggest about the relative strength of attraction between particles in each substance
Water has the strongest intermolecular forces followed by ethanol and diethyl ether has the least intermolecular forces.
From the table, we can see the vapor pressures of water, ethanol and diethyl ether. The boiling point of water is 100°C, the boiling point of ethanol is 80°C while the boiling point of diethyl ether is 40°C.
We can see that the vapor pressures and approximate normal boiling points of the substances varies with the nature of intermolecular bond forces in the molecule.
Water has highest boiling point and the lowest vapor pressure followed by ethanol. Diethyl ether has the highest vapor pressure and lowest boiling point from the data in the table.
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List key terms associated with the carbon cycle
The main parts of the carbon cycle are photosynthesis, respiration, diffusion, absorption, fossil fuel burning, and land use.
The Periodic table below shows major regions in different colors. In this periodic table, which type of element is shown in green boxes?
[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]
The Correct choice is~ B
The elements shown in green boxes are ~ Metalloids
help! ill give brainliest
Answer:
Option B
Explanation:
Magnesium is an alkali earth metal and chlorine is a nonmetal. Due to this, and their differences in electronegativity, the elements form an ionic bond. Since magnesium has two valence electrons, it will give them up to two chlorine atoms (which has 7 valence electrons), which needs them to complete its octet. From this, magnesium forms a cation, and will have the ion formula Mg(2+). The two chlorine atoms form anions, and will have the ion formula Cl(1-).
Terms:
Cation: a positively charged ionAnion: a negatively charge ion.Electronegativity: the tendency of an atom in a molecule to attract the shared pair of electrons towards itself.How many atoms...
NAC2H3O2
Answer:
one Sodium (Na) atom, two oxygen (O) atoms, two carbon (C) atoms, and three hydrogens (H) atoms
Explanation:
A student wants to show the transfer of heat energy without matter which investigation design would best help the student
A) an investigation of radiation through a current in a fluid
B) an investigation of radiation through electromagnetic waves
C) an investigation of conduction through collisions between particles in space
D) an investigation of conduction through the movement of particles through a solid
Answer:
C
Explanation:
According to the concept of thermal energy, transfer of heat energy can be depicted by investigation of conduction through collisions between particles in space.
What is thermal energy?Thermal energy is defined as a type of energy which is contained within a system which is responsible for temperature rise.Heat is a type of thermal energy.It is concerned with the first law of thermodynamics.
Thermal energy arises from friction and drag.It includes the internal energy or enthalpy of a body of matter and radiation.It is related to internal energy and heat .It arises when a substance whose molecules or atoms are vibrating faster.
These vibrating molecules and atoms collide and as a result of which heat is generated in a substance , more the collision of particles , higher is the thermal energy.
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Finding dead insects or mouse droppings in the kitchen indicates which of the following: Pest infestation Chemical contamination Food spoilage Cross contamination
Finding dead insects or mouse droppings in the kitchen is an indication of pest infestation.
Pests are living organisms that are capable of spreading diseases, causing economic damages, or generally constituting nuisance to the environment.
Pest infestation occurs when there is a high number of pests in the environment. When this occurs, their activities are felt in the environment in terms of causing a nuisance, and damaging properties or contaminating foods.
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5. Which element would form
covalent bond with Oxygen (0)
Sodium (Na)
Calcium (Ca)
Aluminum (AI)
Selenium (Se)
What is inertia?(1 point)
A. a force that acts on an object at rest
B. the motion of an object
C. an object’s resistance to a change its motion
D. the speed and direction of an object in motion
Answer:
I think it's C. hope this helps:)
Which of these is the condensed structural formula for an alkane with four carbon
atoms?
O CH3CH2CH2CH3
H
HLH
1C
H
C2
LH
I
C
HTH Н
H
0-I
I
क
H
OCH3CHCHCH3
OC-C-C-C
Answer:
First option
Explanation:
The option that says CH3CH2CH2CH3 is the correct option (I hope that I am right because the order of the answers is not very clear :/)
Stems are important plant structures because they _________.
A.
are the main sites of photosynthesis for plants
B.
are the only site of water and nutrient transport
C.
allow plants to absorb water and nutrients from the soil
D.
give the plant structure and support
Answer:
D
Explanation:
supports the plant,leaves and flowers
4. A student performs four trials of an investigation to determine the boiling point of water. How should the student handle the results?
A. The student should take the average of the minimum and maximum value of the results.
B. The student should use the value that is closest to 100ºC.
C. The student should use the maximum value of the results.
D. The student should take the average of the results from all four trials.
Answer:
i think its D
Explanation:
In order to get maximum accuracy, student should take average of results from all four trials.
What is accuracy?Accuracy in terms of chemistry can be defined as to how close a measurement is to the true value.There are three types of accuracy:
1) Point accuracy-It means accuracy is present at that point of scale only.It does not give any information about the accuracy of the instrument.
2)Percentage of true value--It is the accuracy which is determined by identifying accuracy of the instrument and comparing it with the measured true value.
3)Percentage of scale range- It is the accuracy which determines accuracy of the measurement.
Accuracy in case of instruments is neglected up to ±0.5 percent.Accuracy of measurements can be increased by taking multiple measurements and taking into account human errors.
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How does using more water in a beaker affect the solubility in an experiment?
Identify the six parts of the DNA molecule.
The six parts of DNA serially are A) adenine B) thymine C) Sugars D) Phosphate E) Guanine F) Cytosine.
What is DNA?DNA is a hereditary material which is present in human beings as well as all other living organisms. Every cell which is present in an organism's body has DNA which is the same. Most of the DNA is situated in the cell's nucleus and small amount of it can be found in the cell's mitochondria as well.
Information which is stored in DNA is stored as codes made up of four chemical bases namely, adenine, thymine , cytosine and guanine.Human DNA consists of 3 billion bases .The order of the bases determines information which is required for building and maintaining an organism.
DNA bases are capable of pairing up with each other. Adenine pairs with thymine and guanine pairs up with cytosine .Each base is also attached to a sugar molecule and a phosphate group. A base, phosphate sugar are together called as nucleotides.
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please answer, the question is attached below/above
Answer: No
Explanation: O is a recessive trait so at least there is a mutation, then no.
Seratonin is a neurotransmitter. The ratio of C atoms to N atoms is____
Answer:
5:1
Explanation:
The molecular formula of serotonin is C10H12N2O. Therefore, the ratio of C atoms to N atoms is 5:1, because you divide 10 and 2 by 2, and then you get 5:1.
Phản ứng phân hủy của 1 este trong môi trường kiềm: RCOOR’ + NaOH → RCOONa + R’OH
Để một nửa lượng ban đầu của RCOOR’ và NaOH chuyển thành sản phẩm ở 270C cần thời gian là 200
phút. Hỏi ở 570C cũng để chuyển một nửa lượng ban đầu của RCOOR’ và NaOH thành sản phẩm thì cần
bao nhiêu phút? Cho biết hệ số nhiệt độ của phản ứng trên = 2,8.
13500 mL convert to milliliters of mercury
Answer:approximately 5.627 × 1019 milliliters
Explanation:
give some practical examples where prefixes are used
What is the empirical formula of CoH1803? (4 points)
-O CH30
-C₂H50
-C₂H₂O
-O C₂H5O5
Answer:
-O CH30
Explanation:
My Head Is About To Explode
If a barometer were built using water (d=1.0 g/cm3) instead of mercury (d=13.6 g/cm3), would the column of water be higher than, lower than, or the same as the column of mercury at 1.00 atm? If the level is different, by what factor? Explain.
Mercury is a compound denser than water and when this happen, it stays lower.
So, in this case, water stays higher than mercury because its density is low.
The level is different by a factor of 13.6 times taller.
can someone tell me how to find moles in acid&base equations (simple explination pls)
Answer:
When the base neutralizes the acid, the number of moles of H+ = the number of moles of OH-. Therefore, the number of moles of H+ = 0.0125 moles. Every mole of HCl will produce one mole of H+; therefore, the number of moles of HCl = number of moles of H+. The concentration of the HCl is 0.25 M
Determine the amount in grams of KCl that exists in 20.3 g of a solution that contains 1.14 % KCl by mass 1.14 g KCl
The mass of KCl that exists in 20.3 g of solution containing 1.14% by mass of KCl is 0.23 g
From the question given above, the following data were obtained:
Mass of solution = 20.3 g
Percentage of KCl = 1.14% = 1.14 / 100 = 0.0114
Mass of KCl =?[tex]Percentage = \frac{mass of solute}{mass of solution} * 100\\\\0.0114 = \frac{mass of KCl}{20.3} \\\\[/tex]
Cross multiply
Mass of KCl = 0.0114 × 20.3
Mass of KCl = 0.23 gTherefore, the mass of KCl in the solution is 0.23 g
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Which of the following statements is true?
Select one:
a. All the answers are right
b. Aerobic and anaerobic bacteria don’t decompose organic matter
c. Aerobic bacteria produce bad smelling compounds
d. Anaerobic bacteria produce oxygen as one of their decomposition products
e. Anaerobic bacteria function in the absence of oxygen
Which of the sequence best describe how a piece of chicken nugget is digested in the human body?
mouth, esophagus, small intestine, large intestine, stomach
mouth, esophagus, small intestine, large intestine, stomach
mouth, stomach, small intestine, large intestine, esophagus
mouth, stomach, small intestine, large intestine, esophagus
mouth, esophagus, stomach, small intestine, large intestine
mouth, esophagus, stomach, small intestine, large intestine
None of the above
The sequence for the disgestion of a piece of chicken nugget in the human body is: C. mouth, esophagus, stomach, small intestine, large intestine.
What is digestion?Digestion can be defined as a form of catabolic activity that involves the breaking down of food into smaller sizes that can be absorbed as nutrients by the body of a living organism while releasing energy through the process.
Based on the digestive system, the sequence for the disgestion of a piece of chicken nugget in the human body are:
MouthEsophagusStomachSmall intestineLarge intestineRead more on disgestion here: https://brainly.com/question/22686081
What’s the answer to this
Answer: 5
Explanation:
please brainliest me
I believe it is 3
Answer:
Explanation:
Which of the following frequencies of light has the lowest energy?
Answer:
Radio waves have photons with the lowest energies. Microwaves have a little more energy than radio waves. Infrared has still more, followed by visible, ultraviolet, X-rays and gamma rays.A moon orbits in a roughly circular path around a planet with a mass of 8.6 x 1023 kg. The distance from the center of the moon to the center of the planet is 7.04 x 106 meters. Calculate the speed of the moon in m/s.
Explanation:
A moon orbits in a roughly circular path around a planet with a mass of 8.6 x 1023 kg. The distance from the center of the moon to the center of the planet is 7.04 x 106 meters. Calculate the speed of the moon in m/s.